The phrase "to look at the sky" means to direct your eyes upward and observe whatever is happening in the open space above you, such as the clouds, stars, or the color of the sky. Full definition
Maybe just lying down looking at the sky with summer clouds, letting your imagination soar. (cb1gallery.com)
I guess that's why scientist don't rely on just looking at the sky and making assumptions. (religion.blogs.cnn.com)
It is something you can work out in your own mind just by looking at the sky above your head at night and thinking without having to ask anyone. (bookbrowse.com)